Fragrance dispensers are used to add, remove or mask odours through the release of one or more aromatic compounds (i.e. compounds with an agreeable aroma) or through the use of compounds that absorb or neutralise odours. In addition, the compounds that are released can include, or consist of, compounds having an insect repellent property. For convenience, we will refer to all three types of compounds as “fragrance”.
Long-lasting fragrance dispensers primarily consist of a housing within which a reservoir of fragrance is held, together with a wick to gradually evaporate the fragrance into the surrounding air. The reservoir is often defined within a cartridge that can be removed from the housing when exhausted and replaced. An example can be seen in our earlier application EP-A-2113259. These kinds of dispensers do however need to retain a quantity of fragrance, often in liquid form, which can be unpleasant if it escapes from the reservoir and is often an irritant. However, their long life between service intervals makes them attractive in commercial settings such as offices and washrooms.
Attempts to alleviate the problem have been through the use of viscous gels which are less likely to leak from a damaged reservoir than a fluid. However, the aromatic oils and emulsifiers used to ensure homogenous mixing of the oils in the aqueous solution often disrupt the gelling agents such that it is challenging to make a semi-solid gel with a high concentration of perfume. Furthermore, physical contact with the gel can result in the oil being released into the skin, potentially resulting in irritation.
An alternate fragrance delivery method is through the use of ceramic surface impregnated with a fragrance. The porous nature of ceramics enables them to readily take up a fragrance and then later release it into the environment. They have the advantage that the ceramic surface will not deposit significant amounts of oil onto surfaces touching them, so that they may be safely be picked up with bare hands.